So far announced for Download 2010: AC/DC, Deftones, Them Crooked Vultures, Stone Temple Pilots, Bullet For My Valentine, Megadeth, Motörhead, Wolfmother and plenty other quality to be announced yet methinks, hopefully they will include the recently reformed Soundgarden.
Also looking at Benicassim, the lineup so far wouldn't be my thing, but a festival in scorching Spanish sun sounds like a better experience than the usual rainfest we get here for festivals!